Coastal cliff erosion vulnerability on the Canadian east coast (Baie des Chaleurs area): A multi-parameter visualization tool
M. Daigneault, J-L. Bouchardon, B. Guy, 2004. "Coastal cliff erosion vulnerability on the Canadian east coast (Baie des Chaleurs area): A multi-parameter visualization tool", Coastal Chalk Cliff Instability, R. N. Mortimore, A. Duperret
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In order to assess a cliff’s vulnerability to erosion, researchers must consider a number of parameters that collectively account for all possible erosional processes. The authors have developed a radial diagram that allows the most active processes of erosion to be visualized (e.g. hydrodynamic, gravity-driven or atmospheric), and when such diagrams are présented on a map, they can be used to rapidly identify the contributing erosional processes at a given location. The diagram, developed for the Baie des Chaleurs region (eastern coast of Canada), displays numerical values that represent the relative importance of various weakening parameters for a set of cliffs. In addition, a colour code represents the dominant lithology, and the diagram diameter is a function of the erosion rate. The data for each diagram are based on field observations, experimental work and results of mineralogical and petrophysical analyses. Ten fundamental parameters were used to assess the structural, petrophysical and environmental processes of erosion: porosity, percentage of matrix or cement, homogeneity of the stratification, presence of schistosity, fracture density, number of fracture sets, presence of faults, dip of the strata, effect of waves, and the presence of groundwater. Coastal managers can use these diagrams in conjunction with natural risk maps to estimate the vulnerability of a cliff and decide whether engineering structures are required for préservation.
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Most of the rocky coastlines around the world are subject to active erosion processes. Because of the growing hazard to local communities from coastal cliff retreat, it is necessary to investigate where, when and how cliffs collapse. The results of these studies are vital for the planners and local authorities responsible for safety and access to cliffs and beaches. This volume focuses on the coastal chalk cliffs of the English Channel, where a multidisciplinary approach has been used to understand active coastal cliff recession.
The book is organized around three main themes: the geological factors controlling cliff instability, the marine parameters influencing coastal erosion and the use of some new tools for hazard assessments.
This volume will be of use to academics and professionals working on rocky shores, with an interest in sedimentary geology, stratigraphy, tectonics, geomorphology, engineering geology, coastal engineering and GIS.